IS220PRTDH1BC通用電氣模塊
關(guān)閉或重新分配通道有四種方式可以關(guān)閉或重新分配通道。
1.當(dāng)PLC CPU停止時，所有正在使用的通道都會中止。
2.如果發(fā)生致命錯誤，通道將自動關(guān)閉。
3.可以通過發(fā)出中止通道命令來關(guān)閉通道（或所有通道）。
4.可以通過對信道號發(fā)出另一個命令來重新分配信道的任務(wù)。
這結(jié)束先前的信道操作并開始新的信道操作。發(fā)布通道命令的指南
確保PLC向FIP總線控制器發(fā)送命令塊的速度不超過
總線控制器可以處理它們。如果發(fā)生這種情況，總線控制器將記錄異常事件08，條目2=0024，并記錄PLC故障表條目：“與PLC的背板通信故障；請求丟失”
對于每個通道，一次只能有一個COMREQ函數(shù)掛起。A.COMREQ函數(shù)從在程序中啟動到其
FIP總線控制器已將COMREQ狀態(tài)字更新為非零值。
應(yīng)用程序應(yīng)避免快速使用所有可用的TCP連接。
程序不應(yīng)執(zhí)行以下所有操作。
將重復(fù)次數(shù)設(shè)置為1，然后立即發(fā)出新的COMREQ前一個的完成。
將每個連續(xù)的COMREQ指向同一目標(biāo)設(shè)備或同一信道數(shù)字
為避免使用所有TCP連接，設(shè)置重復(fù)次數(shù)（COMREQ字9）并將讀/寫周期（COMREQ字10和11）設(shè)置為非常大例如60秒。利用這些參數(shù)，程序?qū)l(fā)出第一個COMREQ，
等待COMREQ狀態(tài)（CRS）字變?yōu)?，等待COMREQ狀態(tài)字變?yōu)?，以此類推。下圖和文本解釋了如何使用通信請求打開通信信道。該圖具體說明了建立的操作讀取通道命令。當(dāng)PLC中的COMREQ功能有電力流時，通信請求開始。此時，命令塊數(shù)據(jù)從PLC CPU發(fā)送到FIP總線控制器。
2.對于建立讀通道命令，如果命令塊無效，則立即返回COMREQ狀態(tài)字。如果語法正確，狀態(tài)詞為在下一個重要事件后返回：無法正確建立通道并且及時地或在第一次成功傳輸數(shù)據(jù)時。
一旦通道成功設(shè)置，F(xiàn)IP總線控制器執(zhí)行周期性按照命令塊中的指定讀取。
Closing or Re-tasking a Channel
There are four ways a channel can be closed or re-tasked.
1. When the PLC CPU is stopped, all channels in use are aborted.
2. A channel is automatically closed if a fatal error occurs.
3. A channel (or all channels) can be closed by issuing an Abort Channel command.
4. A channel can be re-tasked by issuing another command for its channel number.
This ends the previous channel operation and begins the new channel operation.
Guidelines for Issuing Channel Commands
Be sure the PLC does not send Command Blocks to the FIP Bus Controller faster than
the Bus Controller can process them. If that happens, the Bus Controller will log an exception event 08, Entry 2=0024 and log the PLC Fault Table entry:
“Backplane Communications with PLC Fault; Lost Request”
For each channel, there should be only one COMREQ function pending at a time. A
COMREQ function is pending from the time it is initiated in the program until its
COMREQ Status Word has been updated to a non-zero value by the FIP Bus Controller.
The application program should avoid quickly using up all available TCP connections.
The program should not do all the following.
Set the number of repetitions to 1 then issue a new COMREQ immediately upon
completion of the prior one.
Direct each successive COMREQ to the same target device or to the same channel
number.
To avoid using up all TCP connections, set the number of repetitions (COMREQ word 9)
to 2 and set the read/write period (COMREQ words 10 and 11) to be very large, for
example, 60 seconds. With these parameters the program will issue the first COMREQ,
wait for the COMREQ Status (CRS) word to turn to 1, then issue the next COMREQ,
wait for the COMREQ Status Word to turn to 1, and so forth.The figure and text below explain how a Communications Request is used to open a
communications channel. The figure specifically illustrates the operation of an Establish
Read Channel command.A Communications Request begins when there is power flow to a COMREQ function in the PLC. At this time, the Command Block data is sent from the PLC CPU to
the FIP Bus Controller.
2. For the Establish Read Channel command, the COMREQ Status word is returned immediately if the Command Block is invalid. If the syntax is correct, the status word is
returned after the next significant event: upon failure to establish a channel correctly
and in a timely manner or upon the first successful transfer of data.
Once the channel is successfully set up, the FIP Bus Controller performs the periodic
reads as specified in the Command Block.
